24 March 1995
To: Distribution:
From: Stan Ecklund
Subject: "IR +- 1m Engineering" Meeting Notes 24 March 1995
Martin showed the latest B1 layout with the vertex detector
drawing included. He reduced the outer diameter of some blocks to
relieve the interference with the vertex cone, and added a block
closest to the IP to compensate. This new block has an
interference with the vertex chamber. Roy will try to modify the
SVD to remove the interference.
Stan showed the calculated integral BL and beam orbits with the
new proposed block geometry compared to the previous. The same
parasitic crossing separation of 3.5 mm is obtained, but the
integral BL is slightly lower (1.5%) which reduces the separation
at Q2. We would like to recover the same BL to not reduce the Q2
septum; even increase it if possible.
The B1 field calculation uses a residual field of 1.05 T. (Catalog
value is a range 1.02 to 1.09 for ShinEtsu R26HS material) No
allowance is put in for block assembly tolerances or azimuthal
inefficiency; i.e. permanent magnet blocks touch their neighbors
with no space between. Presently there is no room for trim coils
for B1 so it must be built to tight tolerances. How does one fine
tune the assembly of B1 to get the design field?
Some of the block inner radii could be reduced, increasing the B1
field if we went to a 4 tip mask. Mike will investigate this. We
should also try to minimize the number of different size/shape
blocks in order to keep costs down.
Time scale requires that the Silicon order must go out in June. A
prototype is expected by late April. Roy's lab is starting to
construct a model of the B1 now.
The machine abort radiation detectors need to be added to the
drawing. Roy will get dimensions from Pat Burchat.
We discussed the possibility of moving the IP longitudinally,
toward the upstream HER beam direction by 5 to 10 mm. This makes
it easier to fit the forward 300 mr cone into the B1 geometry.
The down side is complications to the machine; two which came to
mind were the decrease in parasitic crossing distance on one side,
and changes in quad focusing to move the beta waist. This is not
the baseline but we will consider its feasibility.
Action Items:
1. Add mask cooling channels to drawing. [Martin]
2. Investigate B1 temperature stabilization. [John H.]
3. Try to fix interference of SVD with first block [Roy K]
4. Show location of SVD gimbals on drawing [Roy K]
5. Get radiation detector dimensions for drawing. [Roy K]
6. Send CAD file to LBL. [Martin] .
7 Investigate feasibility of outer side of SmCo block at
300 mr slope. [D. Walz]
8. Investigate machine implications of a 10 mm shift of the IP
[Lattice group, Stan]
9. Investigate a four tip mask and reduced inner block
radius. [Mike]
10. Number and location of holes in support barrel. [Gordon]
11. HOM RF calculations with new mask geometry [S. Heifets]
attachments: Transparencies
Next Meeting: 13:00 Friday 31 March 1995 in the Yellow room with
TV to LBL